# Homework Help: Question about a Force Table - Likelihood of Uncertainty? (lab based)

1. Oct 12, 2007

### twotaileddemon

It's not a homework problem at all.. but it would help me with my understanding in my coursework, so I thought I'd ask here.

I did a lab with a force table recently. I got my measured values easily, and understand the vector nature of forces... but I'm wondering how accurate/precise is a force table? How much uncertainty is there?

For example, I had forces that were 350g @ 350*, 425g @ 270*, and 350g @ 190*.
The equilibrant found was 550g @ 90*.
However, if you do it mathematically by adding the x and y components of the vectors and finding the resultant, and then taking the opposite direction (the equilibrant is opposite in direction but equal in magnitude to it), you get 546.56g. Hence, there is a 3.44g difference from finding the equilibrant experimentally and mathematically/analytically.

Thus, I am asking does anyone know the average "uncertainty" of a force table? As in, how many grams can be added/taken away and how much the angle can differ before the equilibrant shows any difference? Thanks~